Targeting Host Factors Essential for EBV Episome Persistence

About This Grant

Project Summary Epstein-Barr virus (EBV) establishes lifelong infection in humans and contributes to a spectrum of diseases, including infectious mononucleosis, nasopharyngeal carcinoma, oral hairy leukoplakia, post-transplantation lymphoproliferative disorder (PTLD), AIDS-related lymphomas, and certain B-cell malignancies, etc. Despite their substantial health impact, current treatment options remain limited, with no targeted therapies available. Therefore, there is a critical need to develop effective interventions for the treatment of EBV-associated diseases. Within cells, EBV genome is stably maintained as an episome by its encoded viral protein EBNA1 and host cellular factors. While the role of EBNA1 in EBV episome maintenance is well-characterized, the host factors essential for this process remain largely unexplored. We hypothesize that identifying host factors essential for EBV episome maintenance will provide novel therapeutic targets for EBV eradication and the treatment of EBV-associated diseases. In this proposal, we aim to identify host factors essential for EBV episome maintenance through two complementary approaches: 1. Identification of host factors essential for EBV episome maintenance using a genome-wide CRISPR screen. We have developed a novel EBV episome monitoring system, AKATA-EBV-EGFP-Cas9, in which the EBV episome can be monitored via EGFP signal upon IgG induction. Using this system, we will perform a genome-wide CRISPR screen to systematically identify host factors essential for EBV episome maintenance. 2. Determination of host factors that contribute to EBNA1 complex formation. EBNA1 forms complexes with host factors to facilitate EBV maintenance. We hypothesize that host factors critical for EBNA1 complex formation represent potential targets for disrupting EBNA1 function and EBV maintenance. To identify the protein composition of the EBNA1 complex, we have tagged EBNA1 with TurboID, a biotin ligase that uses ATP to biotinylate proximal proteins. In subsequent studies, mass spectrometry will be used to systematically map the proteins involved in EBNA1 complex formation. In summary, this study aims to identify host factors essential for EBV episome maintenance, addressing fundamental knowledge gaps in EBV-host interactions. Our findings will provide critical insights into the mechanisms of EBV persistence and serve as the foundation for a subsequent R01 investigation. The R01 follow-up study will elucidate how EBV hijacks cellular machinery to maintain its episome and evaluate the therapeutic potential of targeting these host factors in EBV-associated diseases.